The Portuguese's desire to add a centre-back has seemingly not abated and United have been linked with Napoli's Kalidou Koulibaly.

But Berbatov believes United should go for a player comfortable on the ball and already familiar with the Premier League if they are to make a move in the January transfer window.

And he says that Maguire, 25, would be an ideal candidate.

“It’s always difficult to buy someone that’s really good in the winter window so if you are lucky enough to buy someone then you need to keep in mind how he’s going to integrate with the team,” the Bulgarian told BT Sport .

“If it’s someone coming from a foreign league it can be more difficult than joining from an English team.

“If you’re buying a central defender then you also need to think about who you’re going to partner him with because you could buy a really good player but if it doesn’t work out then that just causes another problem.

“But I think they need someone at the back that’s comfortable on the ball and don’t buckle under pressure even when someone is attacking you.

“You need to be calm, be able to pass the ball into midfield and carry it. I think they need a player like that.

“I was really impressed with Harry Maguire in the World Cup because he was so composed on the ball and I like that quality in a defender because it benefits the whole team.”

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United face Valencia in the Champions League on Wednesday evening with centre-back Victor Lindelof ruled out and a doubts over the fitness of Chris Smalling and Eric Bailly.

Marcos Rojo and Phil Jones have also had problems this season with Mourinho turning to midfielders Nemanja Matic and Scot McTominay to plug the gaps at times.

Sixth-placed United have conceded 26 Premier League goals during a troubled campaign, more than any other team in the top six.